Electrostatic Hazards in Powder Handling Operations

Charge build-up is observed in most powder handling operations as soon as the powder is highly insulating or the equipment is made from highly insulating material. The ignition probability by discharges due to static electricity can drastically be reduce in practice, if only conductive material is used for all parts of the equipment and installations and if all these parts are safely earthed. The question remains, however, whether the charge retained on a highly insulating product in powder form will be able to ignite this powder, even if the powder is handled and processed in conductive and earthed equipment. Based on extensive research performed during the last decade in this field, ignition of highly insulating powder must be expected under certain circumstances (formation of so-called cone discharges), even if the powder is handled or processed in metallic and earthed equipment

Sustainable change: long-term efforts toward developing a learning organization

Globalization and intensified competition require organizations to change and adapt to dynamic environments in order to stay competitive. This article describes a longitudinal action research study supporting the strategic change of a trading company. The strategic change was accompanied by planned changes in organizational structures and processes, management systems, emerging changes in leadership, and organization members’ attitudes and behaviors, and it was supported by management development activities. Longitudinal data over a 4-year period including participant observation and interviews reveal that a systemic approach, a learning and becoming perspective toward change, trust, an appropriate role perception, and the specific use of management instruments contribute to sustained change that resulted in performance improvements and a move toward a learning organization. We conclude with implications for strategic change and suggestions for further research in this area

Radiating on Oceanic Islands: Patterns and Processes of Speciation in the Land Snail Genus Theba (Risso 1826)

Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island size emphasizes the importance of geographic isolation (allopatry) in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors

Dust Explosions – Hazards, Prevention, and Protection

An overview of the occurrence and characteristics of dust explosions is given. The prerequisites for the formation of a dust explosion are discussed. In particular the importance of the knowledge of the safety characteristic data to assess the ignition hazards due to the different ignition sources occurring in practice is outlined and explained. The measures of explosion prevention and explosion protection are summarized and their advantages, disadvantages, limits and requirements are listed

Electrostatic Hazards in Powder Handling Operations

Charge build-up is observed in most powder handling operations as soon as the powder is highly insulating or the equipment is made from highly insulating material. The ignition probability by discharges due to static electricity can drastically be reduce in practice, if only conductive material is used for all parts of the equipment and installations and if all these parts are safely earthed. The question remains, however, whether the charge retained on a highly insulating product in powder form will be able to ignite this powder, even if the powder is handled and processed in conductive and earthed equipment. Based on extensive research performed during the last decade in this field, ignition of highly insulating powder must be expected under certain circumstances (formation of so-called cone discharges), even if the powder is handled or processed in metallic and earthed equipment. </jats:p